.\"	$OpenBSD: gsc.4,v 1.27 2011/12/21 23:12:03 miod Exp $
.\"
.\"
.\" Copyright (c) 1999 Michael Shalayeff
.\" All rights reserved.
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.Dd $Mdocdate: December 21 2011 $
.Dt GSC 4 hppa
.Os
.Sh NAME
.Nm gsc
.Nd introduction to HP 9000/700 GSC bus support
.Sh SYNOPSIS
.Cd "gsc* at lasi?"
.Cd "gsc* at asp?"
.Cd "gsc* at wax?"
.Sh DESCRIPTION
The General System Connect (GSC) bus
is the core I/O bus for all HP 9000/700 workstations.
All I/O subsystems connect to this bus.
The devices can be either on separate chips, expansion
cards or on an integrated megacell, like the LASI MBA.
.Pp
The
.Tn GSC
bus is a 32-bit wide, address and data multiplexed bus.
In its "standard" implementation it has a maximum throughput of 160MB/s,
the "2x" implementation reaches up to 250MB/s.
Some HPPA CPUs directly attach to this bus, namely the PA7100LC and PA7300LC.
.Pp
As for the expansion cards, there are different form-factors, depending on
bus-speed (standard or 2x) and specific models.
The standard formfactor is the "EISA form-factor"; cards that look like
typical EISA cards with a different connector (100-pin female EBBL).
The Series 712 have their own special type
of GSC expansion cards, called the "GIO form-factor", which is quite small and
mostly has only one VLSI chip on it (in most cases LASI/WAX).
Newer systems sometimes feature the "HSC formfactor", which is a 1U-VME
card-like expansion card with a 100-pin male pin+socket connector.
Mixing cards with different speeds is supported but downgrades
the performance of the whole I/O-subsystem.
.Pp
.Ox
provides support for the following devices:
.Pp
.Bl -tag -width 12n -offset indent -compact
.It Xr arcofi 4
Siemens PSB2160 audio codec
.It Xr com 4
serial communications interface
.It Xr gsckbc 4
PC-style keyboard controller
.It Xr harmony 4
CS4215/AD1849 audio
.It Xr hil 4
introduction to HP-HIL support
.It Xr ie 4
Intel i82596 Ethernet device
.It Xr lpt 4
parallel port driver
.It Xr oosiop 4
.Tn Symbios/NCR
53C700 SCSI I/O Processor
.It Xr osiop 4
.Tn Symbios/NCR
53C710 SCSI I/O Processor
.El
.Pp
Some of these
.Tn GSC
devices also have
.Tn PCI ,
.Tn EISA ,
or
.Tn ISA
equivalents.
These are listed in
.Xr pci 4 ,
.Xr eisa 4 ,
or
.Xr isa 4 .
.Sh SEE ALSO
.Xr asp 4 ,
.Xr cpu 4 ,
.Xr intro 4 ,
.Xr lasi 4 ,
.Xr wax 4
.Sh HISTORY
The
.Nm
driver
appeared in
.Ox 2.6 .
